MPLS (Multiple Protocol Label Switching) technology was proposed in 1997 by IETF (Internet Engineering Task Force). MPLS adopts tags to package the data in upper layers. The MPLS label is added/moved by routers at the edge of a network, it imitates the quick and simple switches in the centre of the network and to perform one-routing-multiple switching for one connecting request and thus improve the network performance. MPLS adopts a simplest technology to perform the transfer from a third layer to a second layer. The MPLS technology has become a predominant technology for the core network.
Ethernet transaction has become a major task of the operators and it has become a tendency to transmit Ethernet transactions in a MPLS network. IETF (Internet Engineering Task Force) PWE3 (edge-to-edge pseudo wires) faculty is drafting a specification which specifies the Ethernet transaction being encapsulated through Martini MPLS with VC (virtual Circuit) label is added to form a PW LSP (pseudo wire label switching path), with multiple PW LSP having identical source and destination ends multiplexed to one tunnel LSP through added tunnel labels, and transmitted in package-switching network.
In PWE3 technology, the setup of LSP may be performed through a RSVP-TE (resource reservation and reserved engineering protocol) signaling (cf. RFC3209 in IETF). The protection of LSP may be performed through adopting LSP linear protection (1:1 or 1+1) and fast reroutes (cf. ITU-T(International Telecommunication Union-Telecommunications) proposal Y.1720).
Typically, an Ethernet adopts a do-its-best principle. When the network is congested, the packet is discarded and thus the transmission of a bandwidth can not be assured. To ensure the transmission of the bandwidth, it is required that the Ethernet have a fair attribute. The fair attribute of an Ethernet transaction refers to such a situation that, when the network is congested while in transmission, different transaction will be assured to have a different bandwidth. Typically the fairness can be embodied by RPR (Resilient Package Ring) (cf. IEEE802.17).
PWE 3 scheme has not included a solution to the fairness for Ethernet transactions, especially when transaction protection occurs. Extra transactions in the protective channel are discarded and thus the fairness in the transaction on the protective LSP can not be ensured.
With the development of the SDH (synchronous digital hierarchy) network, operator's cost in network will be significantly reduced if data traffics can be high-effectively and flexibly transmitted on MPLS.
It will be difficult to provide a solution within the aforesaid technical frame.